Field of the Invention
This invention relates to marine seismic systems and more particularly relates to a deployment and retrieval system for a plurality of autonomous seismic nodes that is fully containerized in a plurality of ISO certified containers.
Description of the Related Art
Marine seismic data acquisition and processing generates a profile (image) of a geophysical structure under the seafloor. Reflection seismology is a method of geophysical exploration to determine the properties of the Earth's subsurface, which is especially helpful in determining an accurate location of oil and gas reservoirs or any targeted features. Marine reflection seismology is based on using a controlled source of energy (typically acoustic energy) that sends the energy through seawater and subsurface geologic formations. The transmitted acoustic energy propagates downwardly through the subsurface as acoustic waves, also referred to as seismic waves or signals. By measuring the time it takes for the reflections or refractions to come back to seismic receivers (also known as seismic data recorders or nodes), it is possible to evaluate the depth of features causing such reflections. These features may be associated with subterranean hydrocarbon deposits or other geological structures of interest.
In general, either ocean bottom cables (OBC) or ocean bottom nodes (OBN) are placed on the seabed. For OBC systems, a cable is placed on the seabed by a surface vessel and may include a large number of seismic sensors, typically connected every 25 or 50 meters into the cable. The cable provides support to the sensors, and acts as a transmission medium for power to the sensors and data received from the sensors. One such commercial system is offered by Sercel under the name SeaRay®. Regarding OBN systems, and as compared to seismic streamers and OBC systems, OBN systems have nodes that are discrete, autonomous units (no direct connection to other nodes or to the marine vessel) where data is stored and recorded during a seismic survey. One such OBN system is offered by the Applicant under the name Trilobit®. For OBN systems, seismic data recorders are placed directly on the ocean bottom by a variety of mechanisms, including by the use of one or more of Autonomous Underwater Vehicles (AUVs), Remotely Operated Vehicles (ROVs), by dropping or diving from a surface or subsurface vessel, or by attaching autonomous nodes to a cable that is deployed behind a marine vessel.
Autonomous ocean bottom nodes are independent seismometers, and in a typical application they are self-contained units comprising a housing, frame, skeleton, or shell that includes various internal components such as geophone and hydrophone sensors, a data recording unit, a reference clock for time synchronization, and a power source. The power sources are typically battery-powered, and in some instances the batteries are rechargeable. In operation, the nodes remain on the seafloor for an extended period of time. Once the data recorders are retrieved, the data is downloaded and batteries may be replaced or recharged in preparation of the next deployment
One known node storage, deployment, and retrieval system is disclosed in U.S. Pat. No. 7,883,292 to Thompson, et al. (“Thompson '292”), and is incorporated herein by reference. Thompson et al. discloses a method and apparatus for storing, deploying and retrieving a plurality of seismic devices, and discloses attaching the node to the deployment line by using a rope, tether, chain, or other cable such as a lanyard that is tied or otherwise fastened to each node and to a node attachment point on the deployment line. U.S. Pat. No. 7,990,803 to Ray et al. (“Ray”) discloses a method for attaching an ocean bottom node to a deployment cable and deploying that node into the water. U.S. Pat. No. 6,024,344 to Buckley, et al. (“Buckley”) also involves attaching seismic nodes to the deployment line. Buckley teaches that each node may be connected to a wire that is then connected to the deployment line though a separate connector. This connecting wire approach is cumbersome because the wires can get tangled or knotted, and the seismic nodes and related wiring can become snagged or tangled with structures or debris in the water or on the sea floor or on the marine vessel. U.S. Pat. No. 8,427,900 to Fleure, et al. (“Fleure”) and U.S. Pat. No. 8,675,446 to Gateman, et al. (“Gateman”) each disclose a deployment line with integral node casings or housings for receiving seismic nodes or data recorders. One problem with integration of the casings with the deployment line is that the deployment line becomes difficult to manage and store. The integrated casings make the line difficult to wind onto spools or otherwise store manageably. In these embodiments, the node casings remain attached directly in-line with the cable, and therefore, this is a difficult and complex operation to separate the electronics sensor package from the node casings. The referenced shortcomings are not intended to be exhaustive, but rather are among many that tend to impair the effectiveness of previously known techniques in seafloor deployment systems; however, those mentioned here are sufficient to demonstrate that the methodologies appearing in the art have not been satisfactory and that a significant need exists for the systems, apparatuses, and techniques described and claimed in this disclosure.
As mentioned above, to perform a seismic survey that deploys and retrieves a large number of autonomous seismic nodes, those nodes must be deployed and retrieved from a marine surface vessel (e.g., a supply vessel). This requires both a supply vessel and a deployment system on the supply vessel. Both have significant limitations.
Existing node deployment systems use large, specially made deployment equipment, machines, and modules/containers that take a long time to install on a standard supply vessel or must have their own dedicated supply vessels. The installation of such equipment may take weeks or months to install properly and may require a dedicated and/or specifically designed vessel to operate such equipment. Such a supply vessel is difficult to find, expensive to rent and/or to buy, and may require significant lead-time to purchase, lease, and/or build. In some instances, the vessels are purposely re-built to integrate the deployment system into the structure of the vessel. When the vessel is not in use and/or is between jobs, rather than removing the deployment equipment and re-installing when the next seismic survey is to be performed, the equipment is typically left on the vessel, and the operator is forced to pay the daily rental rates of the vessel. If a dedicated supply vessel is used, it takes significant time and money to transport that dedicated supply vessel to an intended survey destination around the world. Such systems are costly, time consuming, and ineffective.
A primary issue with existing node deployment systems is actually transporting the node deployment system to the intended survey site and/or port to equip a supply vessel with the node deployment system. Transportation is a highly regulated industry, and existing node deployment systems are not capable of being easily transported. In some instances, the node deployment systems (or portions thereof) are so cumbersome to transport that the intended supply vessel is moved from one location in the world to the node the deployment system's storage or fabrication facility to have the deployment system installed at the storage facility, and then to transit the supply vessel to the intended destination site of the survey. This is a costly and time-consuming process. Further, if the deployment system requires non-standardized shipping methods (which is a requirement of all existing node deployment systems), seismic surveys can be seasonal and at times the transmit times between surveys can be substantial, such as transits from Europe to Asia, Asia to the eastern United States or Europe, and the western United States to Europe.
A container ship is a standard type of cargo ship that carries all of its payload in a container, commonly called shipping containers. A container ship is the predominant method of commercial freight sea transport and carries most seagoing non-bulk cargo around the world. Containerization (e.g., the shipping of goods via standard containers in a standard shipping container) significantly reduces shipping time and costs, and much like the airline industry, has a set schedule of times, destinations, and routes for ports and routes all around the world. However, the transportation industry has regulated container ships and sea transportation, and only ISO certified containers may be used on a container ship. The ISO regulations require that the ISO certified container meets certain size, strength, and durability requirements. An ISO container has a maximum weight limitation. This standardization allows rapid movement, placement, and fastening of containers to the container ships. Not all containers are shipping containers, and not all shipping containers are ISO certified containers. While non-ISO certified containers may be able to transport via air, truck, or train, typically only ISO certified containers are capable of being transported via a container ship.
All current node deployment systems cannot be fully transported to an intended seismic survey location with normal or standardized methods of transportation, particularly as to the use of container ships. Some of the existing node deployment systems use equipment and machines that must be transported by themselves (if too large) and/or installed directly on a dedicated transport vessel. The transportation of such equipment to an intended destination may take months to complete, is very costly, and requires specific transportation vessels that are not easily obtainable. Other existing deployment systems may partially transport such equipment in specially made modules/containers or even some of the equipment in standardized shipping containers, but not all of the equipment can be or is transported via such standardized shipping containers. Further, once the equipment reaches the vessel, even if partially transported in standardized containers, much of the equipment must be removed from the containers and separately installed to the vessel, which takes weeks and/or months to install. Such transportation procedures are costly, time consuming, and ineffective.
Thus, if a node deployment system wants to be transported via a container ship—which is the most cost effective and time sensitive approach to transport the deployment system to the intended survey destination and/or supply vessel—it must be located in one or more ISO certified containers. However, existing deployment systems cannot be entirely transferred via ISO certified containers. Most node deployment systems use large, specially made deployment equipment, machines, winches, and modules/containers that cannot fit on standard container ships (i.e., they are not located within ISO certified containers). Even if some of the components could be shipped via a container ship, the mobilization/installation of a deployment system on a supply vessel is dependent upon the components that take the longest time to get to the supply vessel.
What is needed is a node deployment and retrieval system that is fully autonomous and may be stored, transported, and operated in a cost effective and time sensitive manner. A system is needed that can fully transport, store, and operate all of such a system in CSC approved ISO containers that can be transported via standard shipping routes and mobilized on a suitable vessel. A deployment system is needed that can be easily and quickly installed and/or mobilized on any number of readily available marine vessels.
The disclosed node deployment and retrieval system utilizes CSC approved ISO containers to house all of the necessary deployment/retrieval components for storage, transport, and use on the back deck of a standard marine vessel. No other commercial system utilizes such an approach. Such a system is safer and saves significant money and time for each seismic survey operation.